The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Compressors are used in a wide variety of industrial and residential applications to circulate refrigerant within a refrigeration, heat pump, HVAC, or chiller system (generically referred to as “refrigeration systems”) to provide a desired heating and/or cooling effect. In any of the foregoing applications, the compressor should provide consistent and efficient operation to ensure that the particular refrigeration system functions properly.
Refrigeration systems and associated compressors may include a protection device that intermittently restricts power to the compressor to prevent operation of the compressor and associated components of the refrigeration system (i.e., evaporator, condenser, etc.) when conditions are unfavorable. For example, when a particular fault is detected within the compressor, the protection device may restrict power to the compressor to prevent operation of the compressor and refrigeration system under such conditions.
The types of faults that may cause protection concerns include electrical, mechanical, and system faults. Electrical faults typically have a direct effect on an electrical motor associated with the compressor, while mechanical faults generally include faulty bearings or broken parts. Mechanical faults often raise a temperature of working components within the compressor and, thus, may cause malfunction of, and possible damage to, the compressor.
In addition to electrical and mechanical faults associated with the compressor, the refrigeration system components may be affected by system faults attributed to system conditions such as an adverse level of fluid disposed within the system or to a blocked-flow condition external to the compressor. Such system conditions may raise an internal compressor temperature or pressure to high levels, thereby damaging the compressor and causing system inefficiencies and/or malfunctions. To prevent system and compressor damage or malfunctions, the compressor may be shut down by the protection system when any of the aforementioned conditions are present.
Conventional protection systems may sense temperature and/or pressure parameters as discrete switches to interrupt power supplied to the electrical motor of the compressor should a predetermined temperature or pressure threshold be exceeded. Such protection systems, however, are “reactive” in that they react to compressor and/or refrigeration-system malfunctions and do little to predict or anticipate future malfunctions.